[vtkusers] How to resample RT Dose Grid pixel data with respect to a CT image?

[Jothybasu Selvaraj]

VTKImageData's first pixel is on the lower left bottom, while the
DICOM's first pixel is on the top left.

Why can't you use vtkDICOMImageReader?



On Tue, Oct 9, 2012 at 12:02 PM, Abhishek Gupta <abhishek at meddiff.com> wrote:
> I am using python's VTK wrapper. Python's dicom library to read dicoms and
> wxPython to display images.
> Here's the code that I am using:
> ****************************************************
> dataArray = vtk.vtkUnsignedIntArray()
> for pixel in grid.flat:
>     dataArray.InsertNextValue(pixel)
>
> imageDataArray = vtk.vtkImageData()
> imageDataArray.SetDimensions(no. of rows, no. of columns,1)
> imageDataArray.SetSpacing(2.5,2.5,1)
> imageDataArray.GetPointData().SetScalars(dataArray)
> imageDataArray.Update()
>
> contours = vtk.vtkContourFilter()
> contours.SetInput(imageDataArray)
> contours.GenerateValues(1, level,level)
> contours.Update()
> ****************************************************************
>
>
>
>
> On Tue, Oct 9, 2012 at 4:27 PM, Jothybasu Selvaraj <jothybasu at gmail.com>
> wrote:
>>
>> If you are dealing with DICOM objects in vtk, make sure you are using
>> "FileLowerLeftOn" in the vtk readers.
>>
>> Are you using vtkImageViewer2 for viewing the images?
>>
>>
>>
>> On Tue, Oct 9, 2012 at 11:48 AM, abhishek <abhishek at meddiff.com> wrote:
>> > Hello Jothy,
>> >
>> > Red color structure is at the correct location, which is what I wish to
>> > achieve. The structure generated by my code is displayed in blue color.
>> >
>> > Regards,
>> > Abhishek Gupta
>> >
>> > -----Original Message-----
>> > From: Jothybasu Selvaraj [mailto:jothybasu at gmail.com]
>> > Sent: Tuesday, October 09, 2012 2:44 PM
>> > To: abhishek
>> > Subject: Re: [vtkusers] How to resample RT Dose Grid pixel data with
>> > respect
>> > to a CT image?
>> >
>> > As far as I understand, even if you don't resample your dose grid still
>> > it
>> > should be overlaid properly (unless both have different frame of
>> > reference).
>> >
>> > Could you send apicture of of you get?
>> >
>> > If required you could resample your dose grid using vtkImageResample and
>> > don't forget to update the image attributes using
>> > vtkImageChnageInformation!
>> >
>> > Jothy
>> >
>> >
>> >
>> > On Tue, Oct 9, 2012 at 7:30 AM, abhishek <abhishek at meddiff.com> wrote:
>> >> Dear Users,
>> >>
>> >> I want to draw ISODOSE contours on a CT Image. To generate ISODOSE
>> >> contours, I am using vtkContourFilter class.
>> >> I am using RT DOSE Grid's pixel data to create vtkImageData and giving
>> >> the resulting vtkImage as input to vtkContourFilter.
>> >>
>> >> My problem is that, the RT DOSE Grid's and CT image's pixel spacing
>> >> and image patient position(IPP) are different. This result's in
>> >> generation of wrong contour points.
>> >>
>> >> For reference IPP and Pixel spacing for CT and RT DOSE grid are:
>> >> CT:    [-329.6, -319, -241.3], [1.2461, 1.2461]
>> >> Dose: [-185.1, -180, -546.3], [2.5, 2.5]
>> >>
>> >> I have two questions here:
>> >> 1. I am certainly sure that I will have to some how resample dose's
>> >> pixel data to map on to CT image. How can I do this?
>> >>
>> >> 2. Will vtkImageResample class be useful? If yes, then how can I use
>> >> this class. If no, then what other options do I have?
>> >>
>> >> Regards
>> >> Abhishek.
>> >>
>> >>
>> >>
>> >> --
>> >> View this message in context:
>> >> http://vtk.1045678.n5.nabble.com/How-to-resample-RT-Dose-Grid-pixel-da
>> >> ta-with-respect-to-a-CT-image-tp5716546.html
>> >> Sent from the VTK - Users mailing list archive at Nabble.com.
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>> >
>> >
>> > --
>> > Jothybasu Selvaraj
>> > PhD Student
>> > University of Liverpool
>> > UK
>>
>>
>>
>> --
>> Jothybasu Selvaraj
>> PhD Student
>> University of Liverpool
>> UK
>
>



-- 
Jothybasu Selvaraj
PhD Student
University of Liverpool
UK